垂向层化对海洋生物生产和碳沉降影响的模型研究  

A numerical model study on impact of vertical stratification on biological production and carbon export in the open ocean

作　　者：张黄琛 谭烨辉[1,2,3] ZHANG Huangchen;TAN Yehui(Key Laboratory of Tropical Marine Bio-resources and Ecology,Guangdong Provincial Key Laboratory of Applied Marine Biology,Chinese Academy of Sciences,Guangzhou 510301,China;University of Chinese Academy of Sciences,Beijing 100049,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 510301,China)

机构地区：[1]中国科学院南海海洋研究所,中国科学院热带海洋生物资源与生态重点实验室,广东省应用海洋生物学重点实验室,广州510301 [2]中国科学院大学,北京100049 [3]南方海洋科学与工程广东省实验室,广州510301

出　　处：《生态科学》2024年第3期1-10,共10页Ecological Science

基　　金：国家自然科学基金(31971432,41506161);南方海洋科学与工程广东省实验室(广州)项目(GML2019ZD0405);广东省海洋经济发展项目(GDOE[2019]A32);广东省省级科技计划项目(2017B0303014052)。

摘　　要：受到太阳辐射和淡水输入等影响,海洋的次表层和表层将形成温度跃层和盐度跃层。温度和盐度跃层的存在将使得海洋在不同深度上形成明显的层化现象,阻碍上下层水体间的物质交换。为了研究这种不同深度上的层化现象对海洋生态系统垂向结构的影响,使用了一个简化的一维营养盐-浮游植物-碎屑的模型进行研究。结果显示,无论是表层还是次表层的层化,都会显著地抑制层化区域以下水层营养盐的向上输运,导致层化区以上水层内营养盐浓度的降低。同时,层化区域以上水体浮游植物生物量显著降低,次表层浮游植物生物量最大值层(DCM层)变薄,导致真光层内生物生产力降低;而真光层向深海的碳输出通量也同时降低。层化区域越厚、层化越强,真光层内生物生产越受抑制,碳输出通量越低。相比于表层层化,次表层层化的存在则进一步导致DCM层深度加深,并显著降低DCM层的浓度,使得次表层层化造成的真光层内生物生产力和向深海碳沉降降低得更多。研究证明了在全球气候变化造成海洋增温和冰川融化、极端降雨事件增多造成局部海域表层盐度降低的背景下,海洋垂向层化的增强将对海洋生态系统和全球海洋生物地球化学循环产生不可忽视的影响。Surface warming by solar radiation will form a subsurface thermocline in the ocean,while freshening by river runoffs,rainfall or ice melting will form a halocline in the surface.Thermocline or halocline can induce density stratification at different depths,preventing the vertical mixing of the energy and materials in the ocean.To study the impact of stratification at different depths on the ocean ecosystem,a simplified one-dimensional nutrient-phytoplankton-detritus model is used.Our results show that both surface and subsurface stratification remarkably inhibit the upward transport of nutrient,making the nutrient of the upper layer to be severely depleted.The phytoplankton biomass above the Deep Chl a Maximum(DCM)layer in both scenarios diminish and the DCM layers becomes thinner,resulting in a decrease of the biological production in the euphotic zone and carbon export to the deep ocean.Stronger stratification(weaker vertical mixing)or thicker stratification layer causes greater diminish of biological production and carbon export.Compared with the surface stratification,the subsurface stratification can further induce a deepened and smaller DCM layer and exert a larger impact on the biological production and carbon export.Our study indicates that under the influence of climate change and global warming,the intensified stratification induced by the warmer and fresher upper ocean may have significant impact on the ocean biological production and biogeochemical cycles.

关 键 词：海洋层化 DCM层 生物生产力 碳沉降通量 模型 

分 类 号：Q89[生物学]